Special Issue "Friction and Wear of Engineering Materials "

A special issue of Materials (ISSN 1996-1944).

Deadline for manuscript submissions: closed (31 March 2021).

Special Issue Editors

Prof. Daniele Botto
E-Mail Website1 Website2
Guest Editor
Politecnico di Torino, Torino, Italy
Interests: Contact mechanics, Tribology, Aeroengine dynamics
Dr. Mario Lavella
E-Mail Website
Guest Editor
Politecnico di Torino, Torino, Italy
Interests: Contact mechanics, Tribology, Fatigue, Material modelling, Internal combustion engines

Special Issue Information

Dear Colleagues,

Scientists have studied friction and wear from the late fifteenth century, when Leonardo da Vinci developed the first friction model. More recently, in 1966, H. Peter Jost coined the new word "Tribology" to indicate the combined effect of friction and wear that influences the strength of materials. Previous work on this topic underlined the multidisciplinary nature of friction and wear, which requires knowledge drawn from contact mechanics, materials science, chemistry and physics in general. Friction is one of the main sources of energy dissipation between the contact surfaces and the dissipation of energy is the main cause of wear.

Although the tribology in the broadest sense has studied for so long all the facets of this complex subject have not yet been thoroughly examined and research in this field is going on all over the world.

Materials is providing a Special Issue that is intended to be a means for researchers and engineers of different disciplines to publish and exchange the latest results of their research. This Special Issue will focus on progress in understanding both the fundamental and applied aspects of wear and friction of materials. With the aim of highlighting this concept, this special issue will focus on the following topics:

Wear: Theory, Modeling and Simulation.

Wear: Testing and Monitoring.

Friction and Wear under Vibratory Contact.

Engine Tribology and wear at high temperature.

Wear of Coatings.

Wear of Tools.

Tribocorrosion.

Role of Third Bodies during Wear.

Others.

We warmly invite you to submit a manuscript(s) for this Special Issue. Full papers, communications, and reviews are all welcome.

Prof. Daniele Botto
Dr. Mario Lavella
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2000 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Wear
  • Friction
  • Tribology
  • Fretting
  • Elevated Temperature
  • Material behavior
  • Coatings

Published Papers (12 papers)

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Research

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Open AccessArticle
Tribological Behavior of AlCrSiN-Coated Tool Steel K340 Versus Popular Tool Steel Grades
Materials 2020, 13(21), 4895; https://doi.org/10.3390/ma13214895 - 31 Oct 2020
Cited by 3 | Viewed by 561
Abstract
The tribological performance of metalwork steel tools is of vital importance in both cold and hot working processes. One solution for improving metal tool life is the application of coatings. This paper investigates the differences in quantitative wear behavior and wear mechanisms between [...] Read more.
The tribological performance of metalwork steel tools is of vital importance in both cold and hot working processes. One solution for improving metal tool life is the application of coatings. This paper investigates the differences in quantitative wear behavior and wear mechanisms between AlCrSiN-coated and bare steel K340 and five reference tool steels: X155CrVMo12-1, X37CrMoV5-1, X40CrMoV5-1, 40CrMnMo7 and 90MnCrV8. The investigated tool steels were heat-treated, while K340 was subjected to thermochemical treatment and then coated with an AlCrSiN hard film (K340/AlCrSiN). The hardness, chemical composition, phase structure and microstructure of steels K340 and K340/AlCrSiN were examined. Tribological tests were conducted using the ball-on-disc tester in compliance with the ASTM G99 standard. The tests were performed under dry unidirectional sliding conditions, using an Al2O3 ball as a counterbody. The wear factor and coefficient of friction were estimated and analyzed with respect to hardness and alloying composition of the materials under study. Scanning electron microscopy (SEM) observations were made to identify the sliding wear mechanisms of the analyzed tool steels and physical vapor deposition (PVD)- coated K340 steel. In contrast to the harsh abrasive–adhesive wear mechanism observed for uncoated tool steels, the abrasive wear dominates in case of the AlCrSiN. The deposited thin film effectively prevents the K340 substrate from harsh wear severe degradation. Moreover, thanks to the deposited coating, the K340/AlCrSiN sample has a coefficient of friction (COF) of 0.529 and a wear factor of K = 5.68 × 10−7 m3 N−1 m−1, while the COF of the reference tool steels ranges from 0.70 to 0.89 and their wear factor ranges from 1.68 × 10−5 to 3.67 × 10−5 m3 N−1 m−1. The AlCrSiN deposition reduces the wear of the K340 steel and improves its sliding properties, which makes it a promising method for prolonging the service life of metalwork tools. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Tribological Performance of Environmentally Friendly Bio-Degradable Lubricants Based on a Combination of Boric Acid and Bio-Based Oils
Materials 2020, 13(17), 3892; https://doi.org/10.3390/ma13173892 - 03 Sep 2020
Cited by 2 | Viewed by 588
Abstract
Finding effective and environmentally friendly lubrication to use in sheet metal forming operations presents a substantial environmental and economic challenge to the automotive industry. This paper examines the effectiveness of different lubricants in the reduction of the coefficient of friction (COF) in the [...] Read more.
Finding effective and environmentally friendly lubrication to use in sheet metal forming operations presents a substantial environmental and economic challenge to the automotive industry. This paper examines the effectiveness of different lubricants in the reduction of the coefficient of friction (COF) in the process of sheet metal forming of the low carbon steel sheets. These lubricants are based on a combination of boric acid (H3BO3) and edible vegetable oils, both of which are natural and environmentally friendly. To evaluate the friction characteristics of the lubricants in a forming operation, a strip drawing friction test is used. This test consisted in drawing a specimen in the form of a sheet metal strip between two non-rotating counter-samples with radii of 200 and 10 mm. The effectiveness of environmentally friendly lubricants in reducing the COF was compared to the traditional petroleum-based lubricants which are used in sheet metal-forming operations. The effect of lubricant conditions and tool surface roughness on the value of COFs is studied. It was found that palm oil in both configurations of countersample radius, both as pure oil and with the addition of 5 wt.% of H3BO3, was the most effective in lowering the coefficient of friction. In most of the conditions analysed, the addition of boric acid into vegetable oils leads to an increase in the lubrication efficiency by up to 15% compared to pure oils. The effectiveness of lubrication by olive and rapeseed oils in decreasing the frictional resistances clearly depends on the nominal pressure applied. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Influence of Metallic Deposition on Ceramic Femoral Heads on the Wear Behavior of Artificial Hip Joints: A Simulator Study
Materials 2020, 13(16), 3569; https://doi.org/10.3390/ma13163569 - 12 Aug 2020
Viewed by 547
Abstract
Several retrieval studies have reported on metallic depositions on ceramic femoral heads, but the effect on the wear behavior of artificial hip joints has not been investigated in wear simulator studies. In the present study, retrieved ceramic heads with metallic depositions as third [...] Read more.
Several retrieval studies have reported on metallic depositions on ceramic femoral heads, but the effect on the wear behavior of artificial hip joints has not been investigated in wear simulator studies. In the present study, retrieved ceramic heads with metallic depositions as third particles were tested against cross-linked ultra-high-molecular-weight polyethylene (UHMWPE) liners in a hip wear simulator. The amount of liner wear and expansion of metallic depositions on the heads were determined before and after wear testing with digital microscopy. The surface roughness of the heads was investigated in areas with and without metallic depositions by laser scanning microscopy. After five million load cycles, a non-significant reduction in the metallic formation on the retrieved heads was found. The metallic areas showed a higher surface roughness compared to unconcerned areas. The liners showed a higher wear rate of 1.57 ± 1.36 mg/million cycles for 28 mm heads and 2.42 ± 0.82 mg/million cycles for 36 mm heads with metallic depositions, in comparison with new ceramic heads with a 28 mm size ((−0.06 ± 0.89) mg/million cycles) and 36 mm size ((2.04 ± 0.46) mg/million cycles). Metallic transfer on ceramic heads can lead to an increased surface roughness and higher wear rates at the UHMWPE liners. Therefore, metallic contact of the ceramic femoral head should be avoided. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Effects of Temperature on the Fretting Wear Behavior of 2.25Cr-1Mo Tubes against Gr5C12 Rods
Materials 2020, 13(15), 3388; https://doi.org/10.3390/ma13153388 - 31 Jul 2020
Cited by 1 | Viewed by 647
Abstract
In the heat exchangers of sodium-cooled fast reactors, sodium flow can cause the tubes to vibrate, resulting in fretting wear damage due to the contact between the tubes (2.25Cr-1Mo steel) and their support plate (Gr5C12 alloy). In this work, the effects of temperature [...] Read more.
In the heat exchangers of sodium-cooled fast reactors, sodium flow can cause the tubes to vibrate, resulting in fretting wear damage due to the contact between the tubes (2.25Cr-1Mo steel) and their support plate (Gr5C12 alloy). In this work, the effects of temperature on the fretting wear behavior of a 2.25Cr-1Mo heat transfer tube on a Gr5C12 alloy rod were studied. The results showed that the coefficient of friction (COF) and wear volume increased first and then decreased with the increase in temperature. Moreover, 2.25Cr-1Mo showed great wear performance at high temperatures than at room temperature and 80 °C, because of the antifriction nature of the oxidative layer and the high hardness of the tribological transformed structure layer. As the temperature increased, material transfer and plastic deformation became increasingly obvious, but average wear depth decreased. This provides data support for the practical engineering application of 2.25Cr-1Mo steel at elevated temperatures. Wear mechanisms were found to depend modestly on temperature and largely on normal load. As temperature increases, the wear mechanism gradually changes from abrasive wear to adhesive wear. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Frictional Heating during Braking of the C/C Composite Disc
Materials 2020, 13(12), 2691; https://doi.org/10.3390/ma13122691 - 12 Jun 2020
Cited by 2 | Viewed by 721
Abstract
An analytical model to determine temperature in a single brake disc of multi-disc system is proposed. The model considers the convective cooling on the lateral surfaces of the disc and structure of composite friction material. Calculations were carried out for a disc made [...] Read more.
An analytical model to determine temperature in a single brake disc of multi-disc system is proposed. The model considers the convective cooling on the lateral surfaces of the disc and structure of composite friction material. Calculations were carried out for a disc made of carbon friction composites material Termar-ADF. The influence of heat transfer with environment, length of bundles with fibers, and concentration of fibers in composite on the temperature of the disc was investigated during single braking with constant deceleration. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
The Influence of Laser Surface Remelting on the Tribological Behavior of the ECAP-Processed AZ61 Mg Alloy and AZ61–Al2O3 Metal Matrix Composite
Materials 2020, 13(12), 2688; https://doi.org/10.3390/ma13122688 - 12 Jun 2020
Cited by 2 | Viewed by 663
Abstract
This paper deals with the tribological study of the laser remelted surfaces of the ECAP-processed AZ61 magnesium alloy and AZ61–Al2O3 metal matrix composite with 10 wt.% addition of Al2O3 nanoparticles. The study included the experimental optimization of [...] Read more.
This paper deals with the tribological study of the laser remelted surfaces of the ECAP-processed AZ61 magnesium alloy and AZ61–Al2O3 metal matrix composite with 10 wt.% addition of Al2O3 nanoparticles. The study included the experimental optimization of the laser surface remelting conditions for the investigated materials by employing a 400 W continual wave fiber laser source. Tribological tests were performed in a conventional “ball-on-disc” configuration with a ceramic ZrO2 ball under a 5 N normal load and a sliding speed of 100 mm/s. The results showed that both the incorporation of Al2O3 nanoparticles and the applied laser treatments led to recognizable improvements in the tribological properties of the studied AZ61–Al2O3 composites in comparison with the reference AZ61 alloy. Thus, the best improvement has been obtained for the laser modified AZ61–10 wt.% Al2O3 nanocomposite showing about a 48% decrease in the specific wear rate compared to the laser untreated AZ61 base material. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
The Influence of Microstructure on Abrasive Wear Micro-Mechanisms of the Claddings Produced by Welding Used in Agricultural Soil
Materials 2020, 13(8), 1920; https://doi.org/10.3390/ma13081920 - 19 Apr 2020
Cited by 3 | Viewed by 707
Abstract
Claddings produced by welding are commonly used to increase the durability of the working elements of agricultural tools. The working conditions that occur during the cultivation of agricultural soil determine the wear intensity (different soil fractions, biological, and chemical environment). It was found [...] Read more.
Claddings produced by welding are commonly used to increase the durability of the working elements of agricultural tools. The working conditions that occur during the cultivation of agricultural soil determine the wear intensity (different soil fractions, biological, and chemical environment). It was found that the tested claddings (Fe-Cr-C-Nb system) is characterized by three different layers: hypereutectic (layer I), near eutectic (layer II), and hypoeutectic (layer III). In layer I, micro-cracking and spalling of hard and brittle primary M7C3 carbides resulted in micro-delamination under the impact of larger soil fractions, which increased the wear intensity. Due to the lower fraction of primary M7C3 carbides in layer II, the share of micro-delamination was less significant in comparison to layer I. It was found that niobium carbides are firmly embedded in the matrix and effectively inhibit wear intensity in layer I and layer II. Layer III contained austenite dendrites, a refined eutectic mixture, and also NbC. In this layer, cracks (caused the unfavorable eutectic mixture morphology) were found in the interdendritic spaces at the worn surface. After the penetration of the cladding, there was a "wash-out effect", which resulted in a significant reduction in the durability of the working elements due to abrasive wear. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Tribological Properties of Si3N4-hBN Composite Ceramics Bearing on GCr15 under Seawater Lubrication
Materials 2020, 13(3), 635; https://doi.org/10.3390/ma13030635 - 31 Jan 2020
Cited by 1 | Viewed by 652
Abstract
This paper concerns a comparative study on the tribological properties of Si3N4-10 vol% hBN bearing on GCr15 steel under seawater lubrication and dry friction and fresh-water lubrication by using a pin-on-disc tribometer. The results showed that the lower friction [...] Read more.
This paper concerns a comparative study on the tribological properties of Si3N4-10 vol% hBN bearing on GCr15 steel under seawater lubrication and dry friction and fresh-water lubrication by using a pin-on-disc tribometer. The results showed that the lower friction coefficient (around 0.03) and wear rate (10−6 mm/Nm) of SN10/GCr15 tribopair were obtained under seawater condition. This might be caused by the comprehensive effects of hydrodynamics and boundary lubrication of surface films formed after the tribo-chemical reaction. Despite SN10/GCr15 tribopair having 0.07 friction coefficient in the pure-water environment, the wear mechanismsits were dominated by the adhesive wear and abrasive wear under the dry friction conditions, and delamination, plowing, and plastic deformation occured on the worn surface. The X-ray photoelectron spectroscopy analysis indicated that the products formed after tribo-chemaical reaction were Fe2O3, SiO2, and B2O3 and small amounts of salts from the seawater, and it was these deposits on the worn surface under seawater lubrication conditions that, served to lubricate and protect the wear surface. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Insight into the Effect of TDMs on the Tribological Behaviors of the Ionic Liquid Composite Films
Materials 2020, 13(1), 191; https://doi.org/10.3390/ma13010191 - 02 Jan 2020
Viewed by 615
Abstract
Ionic liquid (IL) combined with 2D materials has evoked considerable attention in the field of lubrication applications because of their speical structure and outstanding lubrication properties. However, the ambiguous effect of the 2D materials on the friction and anti-wear properties of the IL [...] Read more.
Ionic liquid (IL) combined with 2D materials has evoked considerable attention in the field of lubrication applications because of their speical structure and outstanding lubrication properties. However, the ambiguous effect of the 2D materials on the friction and anti-wear properties of the IL needs futher study. Here, we have obtained two families of IL composite films with additives of MoS 2 and graphene via a combined process of spin-coated and curing, and the distinction of the effects of two additives on the tribological performance of the IL films was studied. The friction tests showed that the friction coefficient and anti-wear life of the IL films were greatly enhanced after the addition of MoS 2 or graphene, which could be attributed to the improved load-carrying capacity and the second lubrication phase. Under a low addition content, graphene had more advantages to reduce the friction of the films, and MoS 2 was more beneficial to the tribological properties with the additional content increased. The films with low friction and good anti-wear properties may be valuable for the rational design of lubrication films for the practical engineering applications. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Wear Induced Failure of Automotive Disc Brakes—A Case Study
Materials 2019, 12(24), 4214; https://doi.org/10.3390/ma12244214 - 15 Dec 2019
Cited by 3 | Viewed by 1327
Abstract
This paper investigated a failure in a ventilated disc brake in an automobile. The failed brake disc had been in service for approximately 10 years. The observed failure was in the form of radial cracks that appeared to have initiated at the outer [...] Read more.
This paper investigated a failure in a ventilated disc brake in an automobile. The failed brake disc had been in service for approximately 10 years. The observed failure was in the form of radial cracks that appeared to have initiated at the outer edge of the disc brake. The cracks were rather straight with no branching. Optical microscope, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) were used to study the microstructure of the failed disc. Vickers microhardness test was also used to evaluate the hardness of the samples. Results showed that the root cause of crack formation, in this case, was related to the excessive wear in the brake disc. Different wear mechanisms, namely abrasive and adhesive wear, were recognized in the failed specimen. Moreover, the worn surface in some areas was covered with fine oxide particles. These particles appeared to have a significant contribution toward abrasion. To further understand the wear mechanisms, pin-on-disc experiments were also conducted on the samples. Results of the pin-on-disc experiments were compared and correlated to the results obtained from the failed brake disc. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Open AccessArticle
Comparison of the Friction and Wear Characteristics between Copper and Paper Based Friction Materials
Materials 2019, 12(18), 2988; https://doi.org/10.3390/ma12182988 - 15 Sep 2019
Cited by 2 | Viewed by 793
Abstract
Copper-based friction material (CFM) and paper-based friction material (PFM) are the two most commonly used clutch friction materials. The friction and wear characteristics of these two kinds of friction materials under dry conditions were investigated by the pin-on-disc test over a broad range [...] Read more.
Copper-based friction material (CFM) and paper-based friction material (PFM) are the two most commonly used clutch friction materials. The friction and wear characteristics of these two kinds of friction materials under dry conditions were investigated by the pin-on-disc test over a broad range of applied loads, rotating speeds and ambient temperatures. Before experiments, the running-in test was conducted to stabilize the coefficient of friction (COF) and wear amount of the test samples. After experiments, the metallographic micrographs of the tested samples were presented to investigate the wear mechanisms. Experimental results showed that both the COF and wear depth of the CFM are much greater than these of PFM. The COF of CFM decreases with the increase of applied load, and changes slightly with the variation of rotating speed, whereas it increases first and then decreases with the increase of ambient temperature. However, the COF of PFM decreases dramatically with the increase of the rotating speed and ambient temperature, while it remains stable at first and then decreases slowly as the applied load increases. Additionally, under such three working conditions, the wear depth of CFM changes linearly, while the wear depth of PFM varies greatly. This study can be used as a guide for selecting friction materials for clutches with different applications. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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Review

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Open AccessReview
Practice of Simulation and Life Cycle Assessment in Tribology—A Review
Materials 2020, 13(16), 3489; https://doi.org/10.3390/ma13163489 - 07 Aug 2020
Cited by 1 | Viewed by 818
Abstract
To simulate today’s complex tribo-contact scenarios, a methodological breakdown of a complex design problem into simpler sub-problems is essential to achieve acceptable simulation outcomes. This also helps to manage iterative, hierarchical systems within given computational power. In this paper, the authors reviewed recent [...] Read more.
To simulate today’s complex tribo-contact scenarios, a methodological breakdown of a complex design problem into simpler sub-problems is essential to achieve acceptable simulation outcomes. This also helps to manage iterative, hierarchical systems within given computational power. In this paper, the authors reviewed recent trends of simulation practices in tribology to model tribo-contact scenario and life cycle assessment (LCA) with the help of simulation. With the advancement of modern computers and computing power, increasing effort has been given towards simulation, which not only saves time and resources but also provides meaningful results. Having said that, like every other technique, simulation has some inherent limitations which need to be considered during practice. Keeping this in mind, the pros and cons of both physical experiments and simulation approaches are reviewed together with their interdependency and how one approach can benefit the other. Various simulation techniques are outlined with a focus on machine learning which will dominate simulation approaches in the future. In addition, simulation of tribo-contacts across different length scales and lubrication conditions is discussed in detail. An extension of the simulation approach, together with experimental data, can lead towards LCA of components which will provide us with a better understanding of the efficient usage of limited resources and conservation of both energy and resources. Full article
(This article belongs to the Special Issue Friction and Wear of Engineering Materials )
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